Body adornment is almost as old as humanity itself. To be as God made you has been, historically speaking, not enough for most cultures on the planet. Instead of leaving well alone, people have long been accustomed to pierce, tattoo, and surgically remove certain extremities, all, one assumes, in the belief that these actions improve the body.

Long before the modern age arrived with its ability to transform appearances with plastic and cosmetic surgery, primitive cultures were already doing just that. Őtzi the Iceman, whose corpse dates from Neolithic times, has tattoos; so do several ancient Egyptian mummies, dating back about 2,000 years. Again, there is evidence that female genital cutting (as it is now called) goes back at least two millennia, and male circumcision must be even older. Goodness knows who was the first to pierce the earlobe in order to wear earrings. These are just some common body modifications, with us today: luckily the idea of wearing rings around your neck to lengthen it has not really spread much beyond the so called “giraffe women” of the Paudang nation in Burma.

But it is in our own epoch that body adornment really takes off. With modern surgery there is so much more that you can do. Facelifts, breast enhancements, breast reduction, nose jobs, all these have become not just possible but routine. And we all know of those who have taken these procedures too far. One only has to Google pictures of Michael Jackson as a youth to see the surgical lengths to which he went, producing an appearance that journalists loved to call “bizarre”. The same goes for the lady called “the bride of Wildenstein”, a woman who has ruined her face with repeated cosmetic procedures.

Before one succumbs to the horror of it all – and these extreme examples are truly chilling – it is worth pointing out the difference between plastic surgery and cosmetic surgery. Plastic surgery deals with the recovery of form and function. Much of this is essential – the treatment of burn victims and the reconstruction of, for example, face and hands after an accident. Cosmetic surgery, sometimes called aesthetic surgery, is surgery aimed at improving the appearance. This can sometimes be praiseworthy: if someone has a deformity that seriously affects their quality of life, it is perfectly acceptable, if the risk of surgery is proportionate to the benefit that it will achieve, to correct the deformity.

The idea of proportionality is an important moral tool in considering whether such operations should go ahead. Someone whose life has been made miserable by an over-big nose may well judge surgery a small price to pay if rhinoplasty is going to make their socialisation that much easier. Here, a surgeon and a psychologist would need to consult the patient about the best way forward.

But what if someone just wants to look prettier, and thinks a smaller nose or bigger bust is the way to achieve that? Can one say that the trouble of surgery is justified by the reason put forward?

As a general rule, surgery is never to be embarked on without a serious reason. Psychological reasons may well be serious, but the desire to look better is immediately suspect. Appearances are by their very nature superficial. We change our clothes regularly, and alter our “look” – that is what fashion is all about – but can we really, with justice, take the desire to change to our very flesh itself? It seems not only an extreme measure, but fundamentally misguided. How you look physically matters – it would be foolish to deny that – but it does not matter that much. By all means wear make-up or even fake tan, but spare yourself the knife.

Wearing make-up, even going to the hairdresser, is to surrender to societal pressure to look good; but to surgically reduce your nose in order to look good is a surrender too far. It may be at this point useful to remember the words of the great Ann Widdecombe: “I am toothy, dumpy, ugly, overweight, a spinster – what the hell?” She is as God made her, and we all like her.

To want to modify your appearance is not per se wrong, but as well as proportionality, there are some other moral considerations. First of all, is it really you that wants to make the change? Is this wish the result of a mature and deliberate decision? Or are you being forced into this by outside pressure? Sometimes this sort of pressure is all too easy to recognise (as in the cases of girls forcibly subjected to female genital cutting); sometimes, as in the West, it is much more subtle but nevertheless real.

Secondly, certain surgical procedures are simply wrong. Female genital cutting is a good example of this – it is an intrinsic evil, wrong in itself, whatever the circumstances. The reason is because the procedure can never be for the good of the person who is “cut” in this way. Medically, it can lead to future complications; whichever way, it is impossible to see this as something that is good for the girl who receives it; rather it is something that the girl has imposed on her for her own supposed good by society. Male circumcision, which may have health benefits, is not wrong of itself, and may be right, provided it takes place under the proper conditions. Some cosmetic procedures are trivial, in that they are easily reversed – such as dying your hair, or shaving. Others are serious, and if there are no serious reasons for them, they are wrong.

Women (and it is almost always women) need to resist the pressure to conform to a particular body shape, usually a body shape that they themselves, if left to their own devices, would never have dreamed of choosing. Think of the hourglass figure, so popular in the 19th century. Some women have a natural hourglass figure, but others went to unnatural lengths to get one, ingesting tapeworms and even having ribs surgically removed. This is not only against the virtue of prudence; it also represents a disproportionate effort to look good and, further than that, it represents a dangerous self-obsession.

Frankly, the way we look is not that important. Beauty is only skin deep, and as St Paul says: “Women should adorn themselves with proper conduct, with modesty and self-control, not with braided hairstyles and gold ornaments, or pearls, or expensive clothes, but rather, as befits women who profess reverence for God, with good deeds” (I Tim 2:9-10). This is not the Apostle being a curmudgeon or a killjoy, but speaking good sense. It is how you are inside that really counts. Overemphasis on appearance is a form of idol worship.

Most people who read this have probably spent some time on their appearance today – even I brushed my hair and teeth this morning, not for my own sake, but for those around me. I am not advocating the adoption of severely utilitarian dress, as sported by the late Madame Mao. I am just saying that we need to keep things in proportion, and that this may be something those who feel under pressure to look different need to hear.